/*
 * Copyright (c) 2007, Ecole Polytechnique Fédérale de Lausanne (EPFL),
 * Audiovisual Communications Laboratory, 1015 Lausanne, Switzerland.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * This file is part of the project SensorScope -- http://sensorscope.epfl.ch
 *
 * @author François Ingelrest
 */

interface Watchdog
{
    /**
     * When the watchdog is enabled, it must be touched at least once
     * every 'deadline' ms. If the application fails to do that, the system
     * reboots. Enabling a watchdog that is already enabled is actually
     * equivalent to 'changeDeadline(deadline)'.
     *
     * @param deadline Expressed in ms.
    **/
    command void enable(uint32_t deadline);

    /**
     * Disable the watchdog. Disabling a watchdog that is already
     * disabled has no effect.
    **/
    command void disable();

    /**
     * Change the maximum deadline to touch the watchdog.
     *
     * @param deadline Expressed in ms.
    **/
    command void changeDeadline(uint32_t deadline);

    /**
     * Touch the watchdog.
    **/
    command void touch();

    /**
     * Signaled when a deadline has not been met and the system is about to
     * reboot. Can be used to perform a few things before the reboot.
     *
     * Note that this event may not always be signaled, e.g., in case of
     * a general crash of the system. In such case, this component is unable
     * to check deadlines---and thus to signal this event---while the hardware
     * watchdog will nevertheless cause the reboot of the system.
     *
     * @param guilty TRUE when the current watchdog is responsible for
     *               the reboot, FALSE if another watchdog is responsible for it
    **/
    event void fired(bool guilty);
}
